In the field of liquid packaging, it is very common to equip the neck, whether threaded or unthreaded, of a container with a stopper device, generally made from molded plastic, that includes both a globally tubular base, provided to be immobilized around the neck, and a removable cap, in particular pivotably supported by the base. This type of device, commonly designated using the expression “sport-cap,” is used to allow the user to drink directly from the neck of the container, after having freed the cap in a position far enough from the base to allow the flow through that base of liquid contained in the container.
Before the first use of this type of stopper device, i.e. before the first time the cap is opened relative to the base, the cap and the base are connected to one another by tamper-evident means that may be at least partially broken the first time the device is opened. The tamper-evident means thus in principle provide the user with a visual indication as to whether the device he is manipulating has already been opened. This visual indication is blatant when at least part of the tamper-evident means has been completely separated from the rest of the device. However, in that case, that separated portion, which is generally small, poses a safety problem, since it risks being ingested or inhaled, as well as an environmental problem, since the user tends to get rid of it without taking the precaution of placing it in a wastebasket.
To avoid these problems, known embodiments of tamper-evident means consist of having at least part of said means be, after local rupture of one or more limited frangible zones, deformed enough relative to the rest of the device, under the action of the cap moved during opening or under the direct action of the user so as to free the cap to be opened, to provide a visual indication of first opening, the aforementioned portion of the tamper-evident means remaining permanently connected to the device. However, in that case, the visibility of the first opening indication is often limited, which generally requires the user to meticulously inspect the device to determine whether it has been opened a first time. Thus, WO-A-2010/128 888, on which the preamble of claim 1 is based, proposes locking the movable cap using a protruding hook integral with the base: in order to release the cap, the portion thereof engaged with the hook must be deformed enough to release the hook, which requires that the user first move a peripheral strand away which, over the entire length thereof, is initially frangibly connected to the cap and the hook.